Left Behind
by HotaruGFC
Summary: Post DSOD So, spoilers. Mokuba dealing with what happens at the end.
1. Chapter 1

"Seto!" He called into the microphone. He could see his brother's face on the screen as determined as ever. He knew that he could not dissuade him now that he had made the decision. But still, Mokuba felt that he had to try.

"Seto, we haven't even tested the prototype!" His heart was racing as he felt panic rising within. He had to stop him. He heard his brother speak to him, but the pounding of fear within his mind made his words a blur. He saw the system lights turn green on the panel before him.

"Seto! Seto!" He nearly screamed at the image of his brother on the screen. The final light turned green and flashed—ready for launch. He saw his brother's hand move to the controls in the ship.

"Promise me you'll come back." He whispered, feeling hot tears welling in his eyes. His brother's eyes flicked to the camera one last time and a small smile flickered over his lips. In that smile, Mokuba knew that he agreed to that promise. He would do all the could to make it back.

On the screen, Seto Kaiba pressed the code for launch. The ship fell away from the station and hurtled toward the planet below. The screen shifted from his face to the view outside the ship as it fell. Mokuba stared, tears still unshed, at the planet leaping up toward him. A golden light flashed, blinding him briefly, and when he looked back at the screen, there was nothing.

"SETO!" he screamed, tears now falling freely down his cheeks. He could not breath; the air felt too heavy, oppressive.

"Mr. Mokuba," one of the technicians called for his attention, but he could not move. He only stared at the dark screen, hoping that he could see his brother again if he only wished hard enough. "Mr. Mokuba, Sir."

"What?!" he yelled at the technician, who jumped at the fury and pain in the young man's voice.

"I, um…" the technician struggled under the weight of Mokuba's grief. "You should know that we did not register any sort of explosion nor do we read any debris. It looks like the test was a success."

"Test?! This wasn't a fucking test. Tests don't usually send the people who designed them into other dimensions!"

"Be that as it may, sir, it does seem as if Mr. Seto was indeed sent to another dimension."

"Find a way to get him back." Mokuba ordered as he stormed out of the control room. Everyone he passed throughout the building kept their distance as he wove his way through the labyrinth of corridors in the research and development area of the building to the elevator that would take him to the top floor.

He stepped through the door to his office and his phone pinged. He wiped away the tears that steadily streamed down his face as he pulled the device out. Among the various emails and messages regarding the day to day operation of Kaiba Corporation, he had a notification that Seto had transfered all of his company shares to him, making him the de facto head of the company.

"Dammit." He spat, the anger washing over him once more. He realized that Seto had planned for this. It had been three years since the Pharaoh had departed to… the realm of the dead? Some other dimension? Mokuba did not know. Since then, Seto had grown more and more distant and lost. He had given Mokuba more and more responsibility with the company as he retreated, but Mokuba had not realized just how deeply the obsession had rooted. A year prior, Seto had reassembled the Millennium puzzle and tried to have Yugi bring the Pharaoh back. The attempt nearly destroyed the world, and Mokuba had to watch as his brother vanished before him into another dimension for the first time. The Pharaoh eventually did return, ever so briefly, and his mere presence set everything right once more. But that is when Seto found the cube and started on this foolish crusade to meet the Pharaoh once more.

Mokuba punched the wall.

"I can't do this without you." He yelled, hitting the smooth surface once more. "I'm just a kid, Seto. I'm not ready for this." He leaned heavily against the wall. It was cool against his forehead, soothing his anger, but leaving an emptiness within that ached. He slid down the wall until he could curl his knees to his chest. He knew that Seto had been preparing him to take over the company, and that Seto was not much older than he was when he took over Kaiba Corporation, but Mokuba still did not feel up to the task.

"I'm not as smart as you are, Seto. I… I don't know what to do." He leaned his forehead against his knees and let the emptiness consume him.

Mokuba ignored all requests for his attention. There was nothing so critical at this moment that it could not wait. The company would survive a few hours without him, he decided. He was stiff from sitting on the floor when he decided to stand. The way the sun streamed through the window made him realize that he must have sat there most of the day. He stretched as he stood, watching the golden bands of light illuminating the floor.

Taking a deep breath, he walked out of the office and to the room next door. The space was meticulous as ever. Seto had never allowed anything to be out of place. Many people said it was a cold, sterile space, but those people did not know his brother. Mokuba walked across to his brother's desk. He stroked the top of it, smiling at the perfect arrangement of tools that sat there next to a picture of him and Seto from one of the rare moments when they were brothers first, and everything else came second. He had not even realized that a picture of them had been taken from that day. It was from Mokuba's twelfth birthday, and Seto had spent the entire day just with him, doing whatever he had wanted. He looked so happy in the picture. It brought forth another onslaught of tears. Suddenly, the room felt oppressive and Mokuba had to escape. He hurried from his brother's space and locked the door behind him.

He tried to dry his eyes and stem the flood that threatened to fall with every step he took. By the time he reached the street below, he felt he had achieved some measure of success, but he still felt lost. The valet asked if he needed a car, but he waved him off dismissively. He needed to walk, to clear his head. It was something that Seto never understood, how movement helped him think. Seto always tinkered with things when he needed to think, but Mokuba could never sit still and had a difficult time multitasking with things so complex as inventing new technology and solving problems. So he walked. And thought. He tried to figure out how things would work now that Seto was gone. Not gone, he reminded himself, in another dimension. But he could not be rational. He felt that Seto would chide him for his inability to compartmentalize his grief, but it was not something he could simply set aside. So he walked on, without a goal or destination. His phone kept pinging at him, so he turned it to silent. He did not want to be disturbed and did not think he could handle company business right at this moment.

Eventually he found himself in front of a small game shop across town.

"Yugi." He said, looking at the light through the door. Night was beginning to fall and the street lights were starting to come on. He knew the store would be closing soon, but he could not bring himself to move. So he stood there, staring, thinking. His brother would probably disapprove, but aside from himself, Yugi was the closest thing Seto had to a real friend. He had also helped Mokuba out on a number of occasions. He felt the tears threatening again. As he reached out for the door, he heard a voice call to him.

"Mokuba?"

Mokuba turned to see Yugi standing, surprised, on the sidewalk a few feet away. He was bathed by the streetlight's glow, which made him shine like the Pharaoh had that day the world almost ended. Mokuba noticed that he once again wore the puzzle around his neck.

"Mokuba, what's wrong?" Yugi closed the distance between them and placed a hand on his shoulder. Mokuba realized that he must have seen the tears in his eyes, as Yugi blanched when he looked at him more closely. "What happened?" Mokuba saw so much of the Pharaoh in him, in how he had grown the last few years, but his eyes were kind and gentle and completely Yugi's.

"Seto…" Mokuba sniffled. "Seto's gone." He managed to get the words out in a whisper. As he did so, he felt Yugi wrap his arms around him protectively and pull him close. Mokuba could no longer stop the flood of tears as he cried on the shoulder of his brother's rival—and only friend. He could not be sure, but Mokuba thought he felt a few tears fall that were not his as he gave into his grief and mourned his brother.


	2. Chapter 2

"Tell me what happened, Mokuba." Yugi said as he handed over a cup of hot tea. Mokuba wrapped himself more tightly in the blanket that Yugi's grandfather had wrapped around his shoulders. He looked up absently at Yugi as the cup was pressed into his hands. Its warmth was comforting, but it did nothing to heal the hole inside his heart.

"He… After the duel with Diva, he… well he found the cube that Diva was using." Mokuba took a sip of the steaming liquid. It burned as it slid down his throat. He was relieved by the pain as he had felt numb otherwise.

"The artifact that the Plana used to travel between dimensions?" Yugi asked. His grandfather watched the unfolding conversation in confusion. Mokuba nodded from behind the cup.

"Seto's been experimenting with it, trying to figure out how it works. He had it with him when he…" Mokuba trailed off, feeling his eyes filling once more. "It was with him when he left."

"It's only been a couple of months since that duel. I'm surprised that he got it figured out so quickly. I know he's smart, but still… transdimensional travel isn't something that is on anyone's radar, technologically anyway."

"He's been working on it for a while, actually. The actual ship was finished before we found the puzzle." Mokuba sipped some more of the tea. Despite everything that Seto was or did, Mokuba was always impressed by his brother's capacity for creativity and problem solving.

"Huh." Yugi said thoughtfully.

"He thought the puzzle would be an easier way to get to… well, to him. But you know my brother, he always has a contingency plan. If you couldn't use the puzzle to summon him, he thought the puzzle could be used as a key to unlock the doorway. I guess the cube was just a better key."

"I don't think the puzzle would have worked. I'm no engineer or anything, but…" Yugi took the puzzle from his neck. "It feels… dead. Like all the magic was drained out of it when Atem left." He placed it on the table in front of them. "The only thing in it now are memories." Yugi gazed at the puzzle sadly. Mokuba, also looked at the puzzle. It had been the source of his brother's obsession for so long. Seeing it now laying there, he was both enraged and sad. He was angry at Seto for allowing the simple artifact to consume him so, but sad for Yugi. He had found himself here, he had thought, because Yugi was the closest thing Seto had to a friend, but now he realized that the teenager also had lost someone close to him as Mokuba had been to Seto—perhaps closer even.

Yugi cleared his throat in an effort to shake his own grief from his mind.

"You said that Kaiba had built a craft?"

"Yeah, though I never saw it in person. It was on the space station." Mokuba swirled the loose bits of tea in his cup.

"Your brother has a space station." Yugi chuckled. "Now why does that not surprise me?" Mokuba smiled.

"Gozaburo had started it, but we abandoned it when Seto took over. Still, he did order it finished after the Battle City tournament. He said the quiet helped him think. Anyway, he built the craft there because he needed distance to open the door. I… I don't know all the details. Honestly when he would talk about all of this stuff, most of it went over my head."

They sat sipping tea in silence for a long moment.

"How about a snack?" the elderly man suggested, feeling uncomfortable in the silence.

"That would be great, Grandpa." Yugi replied, looking over his shoulder to the small kitchen.

"There wasn't any wreckage." Mokuba said distantly, his blue-grey eyes staring into the empty space between him and the cup wrapped in his hands. Yugi looked at the kid and hesitantly put his arm around his shoulders. Mokuba leaned into him.

"At least nothing that we could detect. It doesn't mean much, though." Mokuba continued.

"It could mean that it worked." Yugi suggested, hopefully.

"Maybe. It could also mean that the entire thing was vaporized." Mokuba said darkly.

"You can't think like that." Yugi started to say, when the phone rang. His grandfather answered it, but quickly called him over. Mokuba placed his cup on the small table before him and collapsed onto his side on the small sofa. He pulled his knees to his chest and the blanket around him tightly. He was exhausted and wanted to sleep, but every time he closed his eyes he relived the last words his brother had said to him and the agony of his heart breaking in a flash of bright light. At least when his eyes were opened, he felt numb instead. Yugi looked down at him when he walked back to the sofa. He recognized the blank look on Mokuba's face. He sat on the floor next to him.

"You can't give up hope, Mokuba. Listen, if anyone could make the impossible possible, it is your brother. I have no doubt that he is out there, being a thorn in Atem's side and bothering him incessantly for duel after duel."

Mokuba looked at him.

"What was it like?" he asked in a whisper.

Yugi looked at him then, seeing less of the businessman he was becoming and more of the wide-eyed, scared little boy that he barely had time to be.

"What was it like to lose him, Yugi?"

Yugi sighed deeply. He had never really talked to anyone about how it felt to lose Atem. He never thought anyone would understand, and he did not want to burden his friends with it. He had thought about talking to a professional, but quickly realized that no one would believe him. He took a deep breath and let it out slowly.

"It was… hard." He said, knowing it to be a great understatement. "Like I lost part of myself, part of my very being. But it wasn't. There's still a hole in my heart where he was that I don't know how to fill. I think about him all the time."

"Is that why you took the puzzle?" Mokuba asked.

"Yeah. I guess so." Yugi said after some consideration. He had not even thought about it after Diva had been defeated, but technically the puzzle belonged to Kaiba now. He had given it up when he had put it in its resting place, when it shattered, when Atem left. Kaiba had brought it back—likely at no small expense; Kaiba had reassembled it. True, it was also Kaiba that had given it to him once more before passing into oblivion, at least for a short while. But afterward, he had just walked off with it. "It's the only part of him I have left." Yugi found himself staring at the puzzle; his heart willing Atem to appear, but knowing that it was impossible. He took another deep breath.

"Some days are more difficult than others. They all pretty much suck though. At least at first. They get easier. Or you find it easier to distract yourself with other things." Yugi looked at Mokuba who was watching him with all the interest of someone expecting sage wisdom. He tried to smile, but he found he could not. "My friends… I never told them how I felt after he left, not really. I didn't think they would get it—how could they? But they helped, in their own way… as much as they could."

"When Mom and Dad died, I had Seto. He promised to take care of me, to protect me. We've been so close ever since. Now he's gone, and I'm alone."

"But you're not alone, Mokuba. You have friends." Yugi put a hand on his shoulder. "Your brother and I may not see eye to eye on many things… anything really, but I've always thought of you both as my friends. Kaiba was too stubborn to understand that, but you have me, if you need to talk."

"Thanks, Yugi." Mokuba said through sniffles. He wiped tears from his eyes and scrubbed the back of his hand against his nose trying to stymie a sneeze.

"And if the emptiness ever gets to be too much, or it hurts to be alone…" Yugi looked at him pointedly. "I'll be here."


	3. Chapter 3

Everything in the room felt too big—from the desk and hair to the responsibilities of the one who sat upon it. Despite the pressures from the board of directors to fully embrace his role as President and CEO of the company, Mokuba could still feel his brother's presence woven within the very fabric of the room which had been his office. It had been three months since Seto had disappeared, but everyday still felt like a battle.

Who am I kidding, Mokuba thought as he stared blankly at the memos and requests for project approval that needed his attention. It was all too much. He would have given anything for his brother to sweep into the room and take this responsibility from him, though he knew that Seto would not have passed on such responsibility had he not thought Mokuba could handle it. Still, it was too much.

Mokuba shuffled through the stacks of paper one more time, trying again to make himself care about what was on them. He knew that he should look at them and make some decisions regarding them, but he just could not. He knew it was important for the continued success of the company, but it was just too much today. Failing in his attempt to care, he sorted the sheafs of paper into piles based on their topic. He hadn't even wanted to read that much of them. Despite his position at the company, he was still required by law to attend school, and all of these urgent requests had magically appeared in the time he was there. He looked at the tidy piles with an urge to just fling them all off of the desk. He didn't care that he had just worked to make them that way. Looking at them now angered him. He closed his eyes and turned the too big chair around to the floor-to-ceiling window and looked out over the city below.

He could see his brother's mark all over the landscape. His fingerprint was everywhere in the city below. Mokuba had always marveled at Seto's plans to rebuild the world in his image—to make it a more peaceful place, a place where no child would ever have to worry about their future, but looking at the city now, he could see that plan starting to take shape. Very few people knew of that side to his brother, but Seto had built himself a legacy from the ashes of Gozaburo's funeral pyre and it was spread out before him. Mokuba leaned against the window as he looked out, feeling the weight of Seto's legacy pressing upon him. It was now up to him to build upon and protect that legacy. And it was too much.

He thought about the revolver that he had found hidden in one of the drawers of his brother's desk. He knew it had been a remnant of their adoptive father, but he wondered now if the weight of everything had ever gotten to Seto as it is affecting him now. He wondered if Seto had ever been tempted to use it. He wondered what would happen if he used it now.

Mokuba shook the thought from his mind. The weight of it all might be too much right now, but tomorrow will be different. Since Seto had disappeared, everyday was different. Some days were good and everything seemed fine; school was easy and he was able to do the job he needed to do. Other days were like today, where he feels like he's drowning. He glanced at the clock on his phone and sighed. He was expected to be here for at least four more hours, trying to keep the company afloat. And after that, he still had homework. He sighed and reached out to pick up the intercom handset. A voice came over the speaker just before he touched it.

"Mister Kaiba? You have a visitor. He does not have an appointment." The disembodied voice said

"I've told you, my name is Mokuba." He said, his voice thin with annoyance.

"Uh, Yes, sir. But about the visitor? Should I ask him to come back?" Mokuba rolled his eyes. Seto would have done it—sent the person home only to return another day that was more convenient for Seto, even if he was not actually doing anything important. He had once asked Seto why he did it only to have him explain that it was always important to play your hand from a position of strength and power. He realized now what his brother had meant, but Mokuba was not his brother.

"Who is it?" he asked the receptionist.

"He says his name is Yugi Muto? That he's a friend of yours?" she said after a long moment where Mokuba could hear her talking to the visitor. "Should I send him away, Sir?"

"Um, No. Please send him in."

Mokuba was not quite sure how he managed it, but Yugi walked into the office with something akin to a swagger. It had been nearly as long since he had seen the one-time vessel of the ancient spirit as it had been since he had seen his brother.

"Yugi!" he tried and failed to contain his excitement. The arrival had at least broken the dark spiral that Mokuba had found himself traveling. "Good thing Seto's not here or you'd never get in."

A grin spread over Yugi's face.

"You are probably right." He said as he plopped down into a chair. "How are you doing Mokuba? It's been a while." He looked concerned as he leaned forward and propped his elbows on the desk.

"I've been good…" Mokuba answered, standardly, as he tended to answer all of the other well-wishers. He stopped then, sighing as he reminded himself that this was Yugi, the person who had seen him at his most raw the night that Seto had left. "And I'm lying." He finally admitted, both to his friend and himself. Yugi looked at him sympathetically.

"You know, when you hadn't called or come over for a couple of weeks, I had assumed you were busy." Yugi started. "After a month, I figured that you just wanted some time to process things. It took me at least a month before I was ready to really talk about Atem. But after three months… Mokuba, that could only mean that you are lying to yourself about how things are going."

Mokuba leaned back into the tall chair. He felt like such a child sitting in it. He sighed and rubbed the bridge of his nose before pushing his long hair back from his face.

"Yeah. Can I be really honest about something then? Can we both agree on how absolutely insane all of this is?" He asked, finally giving voice to things that had bothered him for the last few months. "I'm fourteen years old, and I'm in charge of shuffling around billions of dollars a day, of making decisions that will impact hundreds or thousands of peoples' lives. And this is actually not just kind of nuts, but completely crazy. No one my age should ever have to make these kinds of decisions."

"Your brother did." Yugi pointed out

"Well, Seto was always a little nuts anyway. As were the people who thought it was a good idea to have a child in control of the company. Like, why didn't they insist on a sort of regency or run most of the decisions by the board first?" He looked at Yugi worriedly. "Don't tell him I said that." He added as if it were even possible. Yugi chuckled.

"Don't worry."

Mokuba laid his head on the desk and rolled a pen back and forth along the slick surface.

"I should be worrying about things like… I don't know, passing English or how to get the girl I have a crush on to like me. I shouldn't be worrying about whether it is a good investment to pursue some new technology." He said softly.

"Oh, Mokuba has a crush on someone?" Yugi raised his eyebrows questioningly. Mokuba sat up again, a slight red tinge coloring his cheeks as he blushed.

"No, it was just an example. Besides, I don't have time for that sort of thing."

Yugi laughed a good hearted fully laugh.

"Maybe you should make the time, then, Mokuba. At the very least, it would give you someone to talk to." Yugi's face fell as he looked at the kid. "It has to be lonely…" Mokuba's expression showed Yugi that he had touched a nerve. He decided to not finish his thought as Mokuba seemed to be on the verge of tears.

"Hey, I have an idea." Yugi said, trying to lighten the mood. "I'm meeting Joey and Tristan in a little bit. Why don't you come with me?"

Mokuba looked at him dumbfounded for a moment. He wondered if Seto had not been so cold and aloof if just hanging out with Yugi and his friends would have been commonplace. He knew Seto would refuse—in fact he would have probably laughed in Yugi's face at the suggestion, only to spiral down into the despair and depression that he had so often denied by throwing himself into his work. But his first instinct was to do the same.

"I can't just leave…" He heard himself say, channeling his brother's spirit, but hoping that Yugi would convince him otherwise.

"Why not? Aren't you the president? Will the company fall apart if you do?" Yugi challenged him much to his relief.

"Um… well…" He could find no good reason. "I guess it won't."

"So take a break. The world won't end if you do." Yugi said with a gentleness in his voice that turned Mokuba's heart.

"But school…" He started to protest, feeling that to not even try to fight the pull to leave would be a betrayal of his brother's spirit.

"What's the teacher going to do if you don't turn something in, Mokuba? Believe me, it's not as bad as you imagine. After all, Joey and Tristan barely turned anything in ever."

Mokuba could not help the laugh that erupted from his gut. He realized that resisting was pointless. Yugi was right; he did need to take a break. He felt like he was being swallowed whole by the responsibilities that had been thrust upon him and either they would have to give or he would.

"Alright. Sure. Let's go." He tried to sound resigned, but could not deny the feeling of excitement rising within him.


End file.
